Certain types of oil wells produce a mixture of oil, gas, and brine. The brine is separated from the oil and gas and recovered, usually in tanks, but its disposal is a major problem.
One technique of disposal is to drill additional wells (called injection wells) where the brine is pumped down into a brine bearing strata in the ground. This is prohibitively expensive for many wells and subjects the environment to further hazard during handling and transportation.
An additional manner in which brine is disposed of is to pump it back into the brine bearing strata in a casing which surrounds the oil and gas production casing of the well from which it was extracted. The disadvantage of doing this is that in order to meet federal and state EPA standards, from time to time it is necessary to pull the entire drill string and surrounding casing and subject the system to testing to make sure that there are no leaks.
There is no current system for continuous monitoring for leaks of brine in which the brine is injected into the brine bearing strata in the ground through a casing surrounding the production casing. Some states are considering banning the practice altogether or, as an alternative, conducting five year mechanical integrity tests on the production and brine disposal casings. These tests are expensive because they involve pulling the entire string and subjecting the system to such testing. As a result, the economics are such that older wells will be plugged rather than tested.